The present invention generally relates to a method of measuring a dielectric material constant and a measuring device for effecting said measuring method, and more particularly, to a method of measuring temperature characteristics of a dielectric sample and a device employed for carrying out said method.
Conventionally, in the technical field referred to above, there has been known a practice in which, with a dielectric sample being disposed within a shield case, a resonance frequency for TE.sub.01n (generally n=1) or TE.sub.01.delta. mode is measured, and then, the shield case is placed in a constant temperature bath for heating to bring it close to a thermal equilibrium state, and thereafter, the resonance frequency is again measured for finding the temperature characteristic of the dielectric sample.
However, by the known practice employing the constant temperature bath as described above, not only is the size of the apparatus undesirably increased, but also, a long time is required before the dielectric sample is heated up to a predetermined temperature to reach a state of equilibrium.
Accordingly, there has been conventionally proposed in Japanese Patent Laid-Open Publication Tokkaisho No. 62-211566, assigned to the same assignee as the present invention, a method of measuring a dielectric material constant and a measuring device employed for that method, in which the conventional problems as referred to above have been eliminated by directly subjecting the dielectric sample to high frequency heating.
In FIG. 14, there is schematically shown the known dielectric material constant measuring device M referred to above, which generally includes a cylindrical shield case S having a bottom wall, with a hollow cylindrical dielectric sample D being fixed approximately at a central portion in the interior of said shield case S by a support rod P, thereby constituting a dielectric resonator R. On the side wall of the shield case S, an input connector I and an output connector O are mounted in opposed positions, each of which connectors is provided with a coupling means such as a coupling loop or the like, while a network analyser W is connected between said input and output connectors I and O. Moreover, another connector Cn also provided with a coupling means such as a coupling loop or the like is further mounted on the side wall of the shield case S, with a high frequency injection device H for heating being connected to said connector Cn.
In the known measuring device as described above, the high frequency injection device H for the heating purpose pours high frequency power into the dielectric resonator R, whereby the dielectric sample D is subjected to high frequency heating. On the other hand, the network analyser W measures the resonance frequency, etc. of the dielectric resonator R coupled between the input and output connectors I and O.
As described above, by measuring the resonance frequency when the dielectric sample D is at the predetermined temperature, the temperature characteristics of the dielectric sample D may be found.
However, in the measuring method of the dielectric material constant and the measuring device employed therefor, based on high frequency heating as referred to above, the problem has been that the measuring device becomes expensive and large in size on the whole, since the very expensive network analyser is employed for measuring the resonance frequency of the dielectric resonator.